Gamma Knife Radiosurgery For Brain Metastases From Breast Cancer - An Initial Treatment Indication According To The Number Of Lesions Less Than Ten Tumors

Shigeo Matsunaga1, Takashi Shuto2, Nobutaka Kawahara1, Jun Suenaga1, Shigeo Inomori1, Hideyo Fujino.1

1Yokohama Rosai Hospital, Yokohama, Japan 2Kanagawa, Japan

Keywords: breast cancer, brain metastasis, gamma knife, outcome, radiosurgery

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     The outcomes after gamma knife radiosurgery (GKS) as an initial treatment were retrospectively analyzed in patients with brain metastases from primary breast cancer as radiosensitive tumor to evaluate the efficacy and the prognostic factors for local tumor control and survival, in comparison with the number of lesions differenced between 1 to 4 and 5 to 10 tumors.
     The medical records were retrospectively reviewed from101 patients with 599 tumors, who harbored less than ten lesions with no finding of cerebral dissemination and controlled primary and extra-cranial metastatic lesion.
     They underwent GKS for metastatic brain tumors from breast cancer between April 1992 and December 2008. These lesions were less than 3cm in maximum diameter with a total tumor volume less than 15cm3.
     Mean tumor volume at GKS was 1.2cm3 with mean prescription dose to tumor margin of 19.0Gy. Radiological imaging showed tumor progression free survival rate was 98% at 1 year after GKS. The significant factors for unfavorable local tumor control were larger tumor volume (p<0.001) and lower marginal dose (p=0.036) by multivariate analysis. New lesion free survival rate was 58% at 1 year. Larger number of lesions (p=0.004) and lower age (p=0.016) were identified as significant worse prognostic factors in multivariate analysis. Median overall survival time was 9 months after initial GKS. Lower Karnofsky performance status score (p=0.002) and presence of active extra-cranial metastases (p=0.016) were significantly correlated with poor result by multivariate analysis, but the number of lesions did not affect the outcome significantly (p=0.814). The cause of death was neurological disease in 11 patients with no significant prognostic factor.
     This is a retrospective study.
     Number of lesions differenced between 1-4 and 5-10 tumors at initial treatment for brain metastases from primary breast cancer did not affect significantly overall and neurological survival after GKS, but larger number of lesions was a significant prognostic factor for appearance of new lesion.
     Therefore we recommend GKS for patients with 5-10 tumors as an initial treatment procedure in substitution of whole brain radiation therapy similar to patients with 1-4 tumors, if we could provide repeat GKS for newly diagnosed lesions.


Project Roles:

S. Matsunaga (), T. Shuto (), N. Kawahara (), J. Suenaga (), S. Inomori (), H. Fujino. ()